Heat pump basics
March 2, 2022
An internal combustion engine (ICE) is relatively inefficient, using only about a third of the fuel's heat energy (BTUs). The rest of the heat energy is “wasted” in friction, cooling and exhaust heat losses. Yet, the ICE’s wastefulness benefits the vehicle's interior heating.Read Article >
Refrigerant reminders
March 1, 2022
It could be a challenging year keeping adequate supplies of R-134a on hand and it will be more expensive.Read Article >
The benefits of MAP-controlled thermostats
February 9, 2022
A customer driving a 2014 BMW 328i arrived at the college's 2nd-year electrical lab reporting his illuminated check engine light. The customer had no complaints other than the light. The vehicle had just over 82K miles showing on the odometer. A student (Phil) assigned to the BMW performed a review with a scan tool, and a single code (P0597 – Thermostat Heater Control Circuit Open) was present.Read Article >
Sometimes it is user error
February 8, 2022
I encountered a situation in the early days of recovery/recycling machines when they had just been introduced. I had set up a machine about four months earlier when the customer purchased it. I went to great lengths to cover proper operation of the unit and the shop owner even attended a certification clinic I conducted.Read Article >
Air contamination in an A/C system can ruin your day
February 2, 2022
I had a memorable encounter with air contamination in the mid 1990s. I was conducting a lot of retrofit clinics at the time and had recently acquired a demo refrigerant identifier which I took to those clinics. At one clinic, there was a technician who was extremely interested in the refrigerant identifier.Read Article >
Read all about it!
February 1, 2022
Read all about it! MACS February 2022 digital issue of ACTION magazine is ready to view.Read Article >
MACS changes leadership
January 31, 2022
MACS is changing leadership. Elvis L. Hoffpauir, is stepping down at the end of January 2022 from his duties as MACS president and chief operating officer to enjoy retirement. Following a 42-year distinguished career at the Mobile Air Climate Systems Association (MACS), Elvis will transition to past president and association advisor.Read Article >
Heater Insight
January 25, 2022
Recently, a customer brought in a 2006 Honda Insight with a heater that was blowing cold but had no other vehicle concerns. A local garage had informed the customer the head gasket had failed; however, the owner felt a second opinion was necessary.Read Article >
Variable output scroll compressors
January 5, 2022
This compressor has been around for quite some time and the vehicles it is used on are getting some age on them. However, they still show up in shops with regularity and there still seem to be a lot of technicians that are not aware of the problem, diagnostic procedure and cure.Read Article >
An overview of electronic variable displacement compressors
December 21, 2021
we have focused on electronically controlled variable displacement compressor operation and behavior. It is important to have a good understanding of how these compressors operate and behave. This is because the percentage of vehicles coming into shops using these units is growing and will continue to grow.Read Article >
The pulse width modulated duty cycle signal
December 7, 2021
Several years ago, when vehicles using these compressors were just starting to show up at shops for service with some regularity, we were searching to find some detailed information about their behavior to use in clinics. There was not a lot of it available, so we borrowed several vehicles and did some videos. The following are some clinic slides produced from one of those videos.Read Article >
Diagnosing electronically controlled compressors
November 30, 2021
When preparing to conduct diagnostics on a system using an electronically controlled variable displacement compressor, the diagnostic process needs to focus on four areas.Read Article >